The process of observing, reasoning, and deducing underpins humanity’s long struggle in securing the natural resources that fuel our advancing societies. Theory never had a role in developing the infrastructure of early civilizations, which instead arose from the institutionalization of knowledge acquired by millennia of observation and trial and error. The first theoretical treatises appeared thousands of years after basic hydrological knowledge had been put into practice in magnificent water works projects throughout the world. It is human nature to observe something and then to ask a question. Logic dictates that theory should follow the answer. However, there has been an insidious progression toward teaching theory as the essential first step in a hydrologist’s education. A reader that opens a hydrology, hydrogeology, or hydraulics text book is typically inundated by formulations of the continuity equation as applied to water, often without any historical or observational grounding for its basis. In contrast, physics, mathematics, geology, and biology textbooks almost always teach from a historical perspective that gives credit to the innovators in their respective fields. More recently, computer modeling has become a mainstay of professional hydrology and has crept into the early stages of student education, further thwarting a student’s innate ability to observe and reason the real world around them.

The roots of hydrology originate in the art of observation, and with the combination of surveying methods and construction engineering many large-scale hydrological works were successfully built by master craftsmen in ancient times. Today’s global economy finances commercial “tradesmen” for similar large-scale projects, while the institutionalized knowledge mostly resides and is corrupted with the educators and researchers in universities. Unfortunate consequences are that observation is subordinated to mathematical formulations and parallel-process computing, innovation is viewed in theoretical terms, applications are divorced from education, and the real world is viewed in needlessly complex terms.

This book is written differently than most textbooks in hydrology. Each chapter begins with an observational description of the hydrological cycle component being discussed, followed by examples, and finally by theoretical considerations. Cartoons found in typical hydrology books are replaced by real examples, and theoretical equations are directly compared to real-world data. This format specifically attempts to align with our natural skills to observe, reason, and deduce, with the hope that the reader will develop an intuitive grasp of mathematical formulations based on observational knowledge. We also introduce water quality and isotopic methods that are typically viewed as exotic measurements, but instead provide a wealth of independent data that clarify questions that cannot be resolved using physical measurements and mathematics alone.

Our intent in this work is to present hydrology in the spirit of the accessible and inspiring observations from which it arose. We are also motivated by the inevitable ascension of the web over printed material as being a first source of information. We hope that the reader will find both enlightenment and useful information in these pages, and that he will freely download and use the contents in a productive way, but that when he does, he will cite the source of that information in the tradition honored by scholars.

This book is in progress and will be updated regularly as material becomes available.